In recent years, with the increase of the resolution of solid-state imaging devices such as COD (charge-coupled device) image sensors and CMOS (complementary metal-oxide-semiconductor) image sensors, the demand for information apparatus having a shooting function, such as digital still cameras, digital video cameras, cell phones (e.g., smartphones), and PDAs (personal digital assistants), has been increasing. In the following description, such information apparatus having a shooting function will be referred to as imaging apparatus.
In such imaging apparatus, a contrast AF (autofocus) method and a phase difference AF method are employed as focus control methods for detecting a distance to a major subject and focusing the apparatus on it. The phase difference AF method is employed in a wide variety of imaging apparatus because it can detect a focus position faster than the contrast AF method.
For example, Patent document 1 discloses an imaging apparatus in which part of the pixels of an imaging device are made phase difference detection pixels and phase difference autofocusing is performed using signals that are read out of the phase difference detection pixels.
Patent document 2 discloses an imaging apparatus in which an exposure is determined using an output signal of a phase difference AF sensor.